As shown in FIG. 1, in a conventional mobile communication terminal 1, at a position of an upper portion of the mobile communication terminal 1 contacting with a user's ear, a speaker unit 10 is formed, and at a position of a lower portion of the mobile communication terminal 1 adjacent to the user's mouth, a microphone 40 is formed, and at a front surface thereof, a liquid crystal display (LCD) 20 as a display unit that outputs a driving state of the mobile communication terminal 1 and a keypad 30 for inputting the user's control command are generally disposed.
In the above-described configuration, the speaker unit 10 is shown in FIG. 2, and the speaker unit 10 includes a speaker 11, an external frame 12 for supporting and protecting the speaker, and a decoration portion 13 formed in a shape such as a convex circular arc shape using a material such as a steel material having luster in a central portion of the external frame for decoration. A controller 2 of the mobile communication terminal 1 formed with a micro controller unit (MCU) or a mobile station modem (MSM) outputs an audio signal received by an RF signal through a vcoder and a digital analog converter (DAC) or an audio signal by reproduction of a multimedia file, and the speaker 11 is vibrated by receiving an input of an audio signal in which the controller 2 outputs and operates to output a sound signal.
However, as described above, in the conventional mobile communication terminal 1, because a user can adjust a magnitude of a output sound volume of the speaker, but even when the output sound volume of the speaker is set to be small, another party may still hear output sound of the speaker and thus there is a problem that the user's private life is not protected.
Further, the conventional mobile communication terminal has a problem that the user cannot appropriately recognize another party's voice or audio sound of reproduced multimedia due to interference by noise at a location having serious noise.
As conventional art for solving the above problem, Korean Patent No. 0687265 (Korean Patent Application No. 2005-0050222) (title: A mobile communication terminal having a bone conduction speaker and the operating method thereof) is disclosed.
That is, as shown in FIGS. 3, 4, and 5, in the conventional art, at a position of an upper portion of a mobile communication terminal 100 contacting with the user's ear, an audio speaker unit 110 is formed, and at a position of a lower portion of the mobile communication terminal 100 adjacent to the user's mouth, a microphone 140 is formed, and at a front surface thereof, an LCD 120 as a display unit for outputting a driving state of the mobile communication terminal 100 and a keypad 130 for inputting a user control command are disposed, and at an adjacent position of the audio speaker unit 110, a bone conduction speaker unit 150 is provided.
The mobile communication terminal 100 includes a controller 101 including an MSM or an MCU for outputting a switching unit control signal that controls voice and data communication by the mobile communication terminal and that outputs an audio signal and that selectively drives the audio speaker unit 110 and the bone conduction speaker unit 150. In an audio signal output terminal of the controller 101, a switching unit 160 for outputting an audio signal by selecting the audio speaker unit 110 and the bone conduction speaker unit 150 is provided, and the controller 101 and the switching unit 160 have a structure that connects an audio signal line 102 for outputting an audio signal and a switching unit control signal line 103 for outputting a switching signal to the switching unit 160. The switching unit 160 includes an audio speaker terminal 161 and a bone conduction speaker terminal 162 and is switched according to a switching signal of the controller 101 to selectively output an audio signal to the audio speaker unit 110 or the bone conduction speaker unit 150. A speaker 111 of the audio speaker unit 110 is connected to the audio speaker terminal 161 of the switching unit 160, and the bone conduction speaker unit 150 is connected to the bone conduction speaker terminal 162 of the switching unit 160. Here, the above-described bone conduction speaker unit 150 transfers a vibration of a bone of a side surface of the user's face to a cochlea of a screw shape positioned at the inside of an eardrum instead of directly inserting into the user's ear and thus the user can recognize sound.
Next, the audio speaker unit 110 includes a speaker 111 and an external frame 112 having a hollow portion and mounted at a front surface of the speaker unit 110 to protect the speaker 111, and in the hollow portion of the external frame 112, a pressing button 113 is supported by a spring 114, and in a lower end portion of the pressing button 113, when the pressing button 113 is pressed, a ground switch 115 that outputs a ground signal to the controller 101 is provided. One end of the ground switch 115 is grounded, and the other end thereof has a structure connected to the controller 101 to be parallel to a reference voltage source VCC. The above-described spring 114 may be replaced with an elastic member of various forms and materials that can provide an elastic force to the pressing button 113.
In the mobile communication terminal 100 having the above-described bone conduction speaker, a method of driving a mobile communication terminal by a selective operation of the audio speaker unit 110 and the bone conduction speaker unit 150 will be described as follows.
First, in a general state, the switching unit 160 of the mobile communication terminal 100 maintains a state in which an audio signal is input to the audio speaker unit 110 (S10). Thereafter, the controller 101 determines whether the pressing button 113 is pressed (S20). By enabling the user to contact the audio speaker unit 110 with a periphery of an ear or a jaw, if the pressing button 113 is pressed, the ground switch 115 is switched to be grounded and thus a low signal is output to the controller 101. When the controller 101 senses pressing of the pressing button 113 by a low signal, the controller 101 outputs a switching control signal that enables the switching unit 160 to be switched to the bone conduction speaker unit 150 through the switching signal line 103. The switching unit 160, having received an input of the switching control signal is switched to input an audio signal input through the audio signal line 102 to the bone conduction speaker unit 150. Thereby, the user can hear an audio signal through a bone conduction speaker without an output of a sound signal, but another party cannot hear a sound signal and thus a private life of the user can be protected (S30). Thereafter, the controller 101 determines whether pressing of the pressing button 113 is released (S40). If pressing of the pressing button 113 is not released, by maintaining a present switching state to the bone conduction speaker unit 150, after outputting audio through the bone conduction speaker unit 150, the controller 101 determines whether pressing of the pressing button is released (S50). Alternatively, as the user separates the audio speaker unit 110 from a contact portion of a periphery of an ear or a jaw bone, the pressing button 113 is returned to an original position by the spring 114 and thus if pressing of the pressing button 113 is released at step S40, a ground switch is separated from the ground and thus a high signal is input again to the controller 101 by the reference voltage source VCC. The controller 101, having received an input of a high signal again outputs a switching control signal for switching to the audio speaker unit 110 to the switching unit 160 and thus the switching unit 160 is switched and is operated to output an audio signal to the audio speaker unit 110. In the above-described processing process, if the pressing button 113 is pressed at step S20, when an audio signal is output by communication or reproduction of a multimedia file, if the user contacts the audio speaker unit 110 with the ear so that the pressing button 113 is not pressed, the switching unit 160 maintains a state that outputs an audio signal to the audio speaker unit 110 (S60).
The conventional art relates to a mobile communication terminal including a bone conduction speaker and an audio speaker and including the bone conduction speaker that outputs an audio signal through the bone conduction speaker when a speaker is positioned at a position other than the ear by sensing the user's speaker contact position and a method of driving the same.
However, the conventional art has the following many problems.
That is, at the conventional art, at a front surface of the terminal, because a receiver hole (speaker unit) is provided, there is a large problem that cannot form an entire front surface of the terminal into a screen window.
Further, in the conventional art, because a vibrator does not attach to a liquid crystal screen or a front panel of the terminal, there is a large problem that an entire front surface of the terminal cannot receive sound.
Further, the conventional art has a problem that sound can be received only when close contacting a speaker portion with the ear, i.e., a problem that sound of high sensitivity cannot be received with a bone conduction function when close contacting the terminal with the ear or a periphery portion of the ear of the face.
Particularly, the conventional art has a problem that peripheral noise is together transferred while communicating, i.e., a large problem that only a communicating person's voice cannot be transmitted regardless of peripheral noise.